@article{RaatzPirhoferWalzlMuelleretal.2021, author = {Raatz, Larissa and Pirhofer-Walzl, Karin and M{\"u}ller, Marina E.H. and Scherber, Christoph and Joshi, Jasmin Radha}, title = {Who is the culprit: Is pest infestation responsible for crop yield losses close to semi-natural habitats?}, series = {Ecology and Evolution}, volume = {11}, journal = {Ecology and Evolution}, edition = {19}, publisher = {Wiley-Blackwell}, address = {Oxford}, issn = {1467-6435}, doi = {10.1002/ece3.8046}, pages = {13232 -- 13246}, year = {2021}, abstract = {Semi-natural habitats (SNHs) are becoming increasingly scarce in modern agricultural landscapes. This may reduce natural ecosystem services such as pest control with its putatively positive effect on crop production. In agreement with other studies, we recently reported wheat yield reductions at field borders which were linked to the type of SNH and the distance to the border. In this experimental landscape-wide study, we asked whether these yield losses have a biotic origin while analyzing fungal seed and fungal leaf pathogens, herbivory of cereal leaf beetles, and weed cover as hypothesized mediators between SNHs and yield. We established experimental winter wheat plots of a single variety within conventionally managed wheat fields at fixed distances either to a hedgerow or to an in-field kettle hole. For each plot, we recorded the fungal infection rate on seeds, fungal infection and herbivory rates on leaves, and weed cover. Using several generalized linear mixed-effects models as well as a structural equation model, we tested the effects of SNHs at a field scale (SNH type and distance to SNH) and at a landscape scale (percentage and diversity of SNHs within a 1000-m radius). In the dry year of 2016, we detected one putative biotic culprit: Weed cover was negatively associated with yield values at a 1-m and 5-m distance from the field border with a SNH. None of the fungal and insect pests, however, significantly affected yield, neither solely nor depending on type of or distance to a SNH. However, the pest groups themselves responded differently to SNH at the field scale and at the landscape scale. Our findings highlight that crop losses at field borders may be caused by biotic culprits; however, their negative impact seems weak and is putatively reduced by conventional farming practices.}, language = {en} } @article{RaatzPirhoferWalzlMuelleretal.2021, author = {Raatz, Larissa and Pirhofer-Walzl, Karin and M{\"u}ller, Marina E.H. and Scherber, Christoph and Joshi, Jasmin Radha}, title = {Who is the culprit: Is pest infestation responsible for crop yield losses close to semi-natural habitats?}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {1866-8372}, doi = {10.25932/publishup-54962}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-549622}, pages = {13232 -- 13246}, year = {2021}, abstract = {Semi-natural habitats (SNHs) are becoming increasingly scarce in modern agricultural landscapes. This may reduce natural ecosystem services such as pest control with its putatively positive effect on crop production. In agreement with other studies, we recently reported wheat yield reductions at field borders which were linked to the type of SNH and the distance to the border. In this experimental landscape-wide study, we asked whether these yield losses have a biotic origin while analyzing fungal seed and fungal leaf pathogens, herbivory of cereal leaf beetles, and weed cover as hypothesized mediators between SNHs and yield. We established experimental winter wheat plots of a single variety within conventionally managed wheat fields at fixed distances either to a hedgerow or to an in-field kettle hole. For each plot, we recorded the fungal infection rate on seeds, fungal infection and herbivory rates on leaves, and weed cover. Using several generalized linear mixed-effects models as well as a structural equation model, we tested the effects of SNHs at a field scale (SNH type and distance to SNH) and at a landscape scale (percentage and diversity of SNHs within a 1000-m radius). In the dry year of 2016, we detected one putative biotic culprit: Weed cover was negatively associated with yield values at a 1-m and 5-m distance from the field border with a SNH. None of the fungal and insect pests, however, significantly affected yield, neither solely nor depending on type of or distance to a SNH. However, the pest groups themselves responded differently to SNH at the field scale and at the landscape scale. Our findings highlight that crop losses at field borders may be caused by biotic culprits; however, their negative impact seems weak and is putatively reduced by conventional farming practices.}, language = {en} } @article{ZwickelKahlRychliketal.2018, author = {Zwickel, Theresa and Kahl, Sandra M. and Rychlik, Michael and M{\"u}ller, Marina E. H.}, title = {Chemotaxonomy of Mycotoxigenic Small-Spored Alternaria Fungi}, series = {Frontiers in microbiology}, volume = {9}, journal = {Frontiers in microbiology}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, issn = {1664-302X}, doi = {10.3389/fmicb.2018.01368}, pages = {20}, year = {2018}, abstract = {Necrotrophic as well as saprophytic small-spored Altemaria (A.) species are annually responsible for major losses of agricultural products, such as cereal crops, associated with the contamination of food and feedstuff with potential health-endangering Altemaria toxins. Knowledge of the metabolic capabilities of different species-groups to form mycotoxins is of importance for a reliable risk assessment. 93 Altemaria strains belonging to the four species groups Alternaria tenuissima, A. arborescens, A. altemata, and A. infectoria were isolated from winter wheat kernels harvested from fields in Germany and Russia and incubated under equal conditions. Chemical analysis by means of an HPLC-MS/MS multi-Alternaria-toxin-method showed that 95\% of all strains were able to form at least one of the targeted 17 non-host specific Altemaria toxins. Simultaneous production of up to 15 (modified) Altemaria toxins by members of the A. tenuissima, A. arborescens, A. altemata species-groups and up to seven toxins by A. infectoria strains was demonstrated. Overall tenuazonic acid was the most extensively formed mycotoxin followed by alternariol and alternariol mono methylether, whereas altertoxin I was the most frequently detected toxin. Sulfoconjugated modifications of alternariol, alternariol mono methylether, altenuisol and altenuene were frequently determined. Unknown perylene quinone derivatives were additionally detected. Strains of the species-group A. infectoria could be segregated from strains of the other three species-groups due to significantly lower toxin levels and the specific production of infectopyrone. Apart from infectopyrone, alterperylenol was also frequently produced by 95\% of the A. infectoria strains. Neither by the concentration nor by the composition of the targeted Altemaria toxins a differentiation between the species-groups A. altemata, A. tenuissima and A. arborescens was possible.}, language = {en} } @misc{ZwickelKahlKlaffkeetal.2017, author = {Zwickel, Theresa and Kahl, Sandra M. and Klaffke, Horst and Rychlik, Michael and M{\"u}ller, Marina E. H.}, title = {Spotlight on the underdogs}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-400438}, pages = {17}, year = {2017}, abstract = {Alternaria (A.) is a genus of widespread fungi capable of producing numerous, possibly health-endangering Alternaria toxins (ATs), which are usually not the focus of attention. The formation of ATs depends on the species and complex interactions of various environmental factors and is not fully understood. In this study the influence of temperature (7 °C, 25 °C), substrate (rice, wheat kernels) and incubation time (4, 7, and 14 days) on the production of thirteen ATs and three sulfoconjugated ATs by three different Alternaria isolates from the species groups A. tenuissima and A. infectoria was determined. High-performance liquid chromatography coupled with tandem mass spectrometry was used for quantification. Under nearly all conditions, tenuazonic acid was the most extensively produced toxin. At 25 °C and with increasing incubation time all toxins were formed in high amounts by the two A. tenuissima strains on both substrates with comparable mycotoxin profiles. However, for some of the toxins, stagnation or a decrease in production was observed from day 7 to 14. As opposed to the A. tenuissima strains, the A. infectoria strain only produced low amounts of ATs, but high concentrations of stemphyltoxin III. The results provide an essential insight into the quantitative in vitro AT formation under different environmental conditions, potentially transferable to different field and storage conditions}, language = {en} } @article{ZwickelKahlKlaffkeetal.2016, author = {Zwickel, Theresa and Kahl, Sandra M. and Klaffke, Horst and Rychlik, Michael and M{\"u}ller, Marina E. H.}, title = {Spotlight on the Underdogs-An Analysis of Underrepresented Alternaria Mycotoxins Formed Depending on Varying Substrate, Time and Temperature Conditions}, series = {Toxins}, volume = {8}, journal = {Toxins}, publisher = {MDPI}, address = {Basel}, issn = {2072-6651}, doi = {10.3390/toxins8110344}, pages = {570 -- 583}, year = {2016}, abstract = {Alternaria (A.) is a genus of widespread fungi capable of producing numerous, possibly health-endangering Alternaria toxins (ATs), which are usually not the focus of attention. The formation of ATs depends on the species and complex interactions of various environmental factors and is not fully understood. In this study the influence of temperature (7 degrees C, 25 degrees C), substrate (rice, wheat kernels) and incubation time (4, 7, and 14 days) on the production of thirteen ATs and three sulfoconjugated ATs by three different Alternaria isolates from the species groups A. tenuissima and A. infectoria was determined. High-performance liquid chromatography coupled with tandem mass spectrometry was used for quantification. Under nearly all conditions, tenuazonic acid was the most extensively produced toxin. At 25 degrees C and with increasing incubation time all toxins were formed in high amounts by the two A. tenuissima strains on both substrates with comparable mycotoxin profiles. However, for some of the toxins, stagnation or a decrease in production was observed from day 7 to 14. As opposed to the A. tenuissima strains, the A. infectoria strain only produced low amounts of ATs, but high concentrations of stemphyltoxin III. The results provide an essential insight into the quantitative in vitro AT formation under different environmental conditions, potentially transferable to different field and storage conditions.}, language = {en} } @phdthesis{Korn2012, author = {Korn, Ulrike}, title = {Der Einfluss unterschiedlich aggressiver Fusarium culmorum- und Fusarium graminearum-Isolate auf die Schadbildauspr{\"a}gung bei Winterweizen sowie die M{\"o}glichkeit der Befallskontrolle mit Mykorrhiza}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-62908}, school = {Universit{\"a}t Potsdam}, year = {2012}, abstract = {Der Einfluss unterschiedlich aggressiver Fusarium culmorum- und F. graminearum-Isolate auf die Schadbildauspr{\"a}gung bei Winterweizen sowie die M{\"o}glichkeit der Befallskontrolle mit Mykorrhiza Die durch Pilzarten der Gattung Fusarium spp. hervorgerufene partielle Taub{\"a}hrigkeit ist ein ernstes Problem im weltweiten Weizenanbau. Eine f{\"u}r die Schaderreger g{\"u}nstige feuchte Witterung zum Zeitpunkt der Weizenbl{\"u}te in Kombination mit befallsf{\"o}rdernden agrotechnischen Maßnahmen l{\"o}st immer wieder Epidemien aus. Haupts{\"a}chlich verursacht durch F. culmorum und F. graminearum f{\"u}hrt eine Erkrankung zu Ertrags- und Qualit{\"a}tseinbußen sowie zu einer Belastung des Ernteguts mit Mykotoxinen, die bereits in niedrigen Konzentrationen toxisch auf den tierischen und menschlichen Organismus wirken. Die am h{\"a}ufigsten vorkommenden Fusarium-Toxine in Weizen sind Deoxynivalenol (DON) und Zearalenon (ZEA). Isolate von F. graminearum- und F. culmorum k{\"o}nnen in ihrem DON- und ZEA-Bildungsverm{\"o}gen und ihrem Potential, Nekrosen zu verursachen, stark variieren. In Laborversuchen (in vitro) wurden F. graminearum- und F. culmorum-Isolate hinsichtlich dieser Eigenschaften (hier als Aggressivit{\"a}t bezeichnet) charakterisiert und anschließend wurde im Feldversuch {\"u}berpr{\"u}ft, ob die in vitro-ermittelte Aggressivit{\"a}t die Schadbildauspr{\"a}gung bei Weizenpflanzen beeinflusst. Nur im ersten Versuchsjahr, das durch hohe Niederschl{\"a}ge gekennzeichnet war, konnte ein Einfluss der Aggressivit{\"a}t und einer zus{\"a}tzlichen Beregnung im Feldversuch nachgewiesen werden. Die als hoch-aggressiv eingestuften Fusarium-Isolate reduzierten unter dem Einfluss der Beregnung den Ertrag und das Tausendkorngewicht. Die Beregnung f{\"u}hrte zu einer Erh{\"o}hung des Pilzwachstums und der DON- und ZEA-Produktion. Ein extrem trockener Sommer verhinderte die Infektion der Weizenpflanzen durch die beimpften Fusarium-Isolate und ein anschließendes Pilzwachstum in den {\"A}hren im zweiten Versuchsjahr. Um den Befall von Weizenpflanzen mit Fusarium spp. vorzubeugen, stehen verschiedene pflanzenbauliche Maßnahmen zur Verf{\"u}gung. Eine M{\"o}glichkeit stellen in diesem Zusammenhang die symbiotischen Mykorrhizapilze (MP) dar. Die Pilze sind in der Lage, Pflanzen zu st{\"a}rken und antagonistisch auf pilzliche Schaderreger zu wirken. Um zu {\"u}berpr{\"u}fen, ob MP dazu beitragen k{\"o}nnten, den Befall von Weizenpflanzen mit Fusarium spp. niedrig zu halten, wurden Weizenpflanzen mit MP und Fusarium spp. beimpft und die Auswirkungen der Interaktionen auf die Weizenpflanzen in einem Klimakammer- und einem Feldversuch getestet. In der Klimakammer wurde eine Reduzierung des Fusarium-Befalls nachgewiesen. Die mykorrhizierten Weizenpflanzen wiesen außerdem h{\"o}here Photosyntheseraten, h{\"o}here Sprosstrockenmassen und mehr {\"A}hren im Vergleich zu den nicht-mykorrhizierten und mit Fusarium-beimpften Weizenpflanzen auf. Insgesamt wurde durch die Mykorrhizierung der negative Einfluss von Fusarium spp. kompensiert. Im Freiland konnte kein Einfluss der MP auf Fusarium spp. beobachtet werden. Im ersten Versuchsjahr f{\"u}hrte das Beimpfen der Weizenpflanzen mit MP zu h{\"o}heren Wurzel- und Sprosstrockenmassen sowie zu h{\"o}heren Tausendkorngewichten im Vergleich zu den mit Fusarium spp.-beimpften Weizenpflanzen. Im zweiten Versuchsjahr konnte dieses Ergebnis nicht wiederholt werden.}, language = {de} }